and as a result, obama has been sinking in the polls. so i think that he might have staunched the bleeding to some extent on the substance romney attacked obama on. and now, it's all up to the heavy weights in the last two rountdz of the fight. >> charles krauthammer, thank you. >> pleasure. >> fox news teamed up with the folks at twitter to find out what you had to say about tonight's debate. twitter keeping tabs on when the discussion on stage triggered a big discussion online. some of the hottest topics trending tonight on the left total volume of tweets throughout the debate, left side of the screen more than 3.5 million tweets, three topics jumped. foreign policy, 26%, second, economy, 21%, third, taxes, at 17%. for perspective, last week's presidential debate ranked in at a total of 0.3 million tweets. a lot of people using twitter tonight. and again, it's at bret br